The nervous system is unique in the vast complexity of thought processes and control actions that it can perform. Each minute it receives literally millions of bits of information from the different sensory nerves and sensory organs and then integrates…
When people descend beneath the sea, the pressure around them increases progressively as they go to greater depths. To keep the lungs from collapsing, air must be supplied at very high pressure to keep them inflated. This maneuver exposes the…
As humans have ascended to higher and higher altitudes in aviation, mountain climbing, and space exploration, it has become progressively more important to understand the effects of altitude and low gas pressures on the human body. This chapter deals with…
Diagnosis and treatment of most respiratory disorders depend heavily on understanding the basic physiological principles of respiration and gas exchange. Some respiratory diseases result from inadequate ventilation. Others are caused by abnormalities of diffusion through the pulmonary membrane or abnormal…
The nervous system normally adjusts the rate of alveolar ventilation to meet the demands of the body almost exactly so that the oxygen partial pressure (P o 2 ) and carbon dioxide partial pressure (P co 2 ) in the…
Once oxygen (O 2 ) has diffused from the alveoli into the pulmonary blood, it is transported to the tissue capillaries almost entirely in combination with hemoglobin. The presence of hemoglobin in the red blood cells allows the blood to…
After the alveoli are ventilated with fresh air, the next step in respiration is diffusion of oxygen (O 2 ) from the alveoli into the pulmonary blood and diffusion of carbon dioxide (CO 2 ) in the opposite direction, out…
The lung has two circulations, a high-pressure, low-flow circulation and a low-pressure, high-flow circulation . The high-pressure, low-flow circulation supplies systemic arterial blood to the trachea, bronchial tree (including the terminal bronchioles), supporting tissues of the lung, and outer coats…
The main functions of respiration are to provide oxygen to the tissues and remove carbon dioxide. The four major components of respiration are the following: (1) pulmonary ventilation , which means the inflow and outflow of air between the atmosphere…
Hemostasis Events The term hemostasis means prevention of blood loss. Whenever a vessel is severed or ruptured, hemostasis is achieved by several mechanisms: (1) vascular constriction; (2) formation of a platelet plug; (3) formation of a blood clot as a…